Some zoas not opening

[wunderlong88]

Hi! I have some zoas that are tightly closed, some that are barely open and one set that is is open just fine. It's probably 10-12 days that I've had the problem, I'm guessing. All the the other soft corals seem happy.

I haven't seen anything bothering them. No fish or inverts and I've been checking and watching alot. I haven't changed locations, lights or anything I'm aware of, except today I noteced the powerheads were a couple of inches lower than normal (from moving and cleaning) and not giving me as much surface agitation. I've moved them back up just now.

I have a 180 with 85 gal sump. It's been running since Jun 2025. I have lots of live rock and live sand from the ocean (Gulf Coast and Australia). I keep lots of fish and some soft corals and a variety of inverts.

I tested today:
Phosphate - .95 ppm (pretty normal for me, I feed a lot!)
Nitrate - 25 pm (same)
Ph 7.7
Kh 7.7
Salinity 1.024/1.025
Temp about 78

I don't dose anything or run anything but a sump full of chaeto and a protein skimmer.
I do about a 15% water change every 10 days, just did one a couple of days ago.

I'm hopeful the powerheads not agitating the surface enough will remedy the problem (not sure when that should make a difference if it does) but wondered if anything else seems suspect?

Thank you.

FYI - Photos have titles to help

 

[DIYreefer]

Have you added any new corals lately? That looks like a pest issue to me.

 

[wunderlong88]

Have you added any new corals lately? That looks like a pest issue to me.

No, I haven't added any new corals in 8 mos.

 

[Privateye]

I would do my typical peroxide dip. I've seen it work wonders and I've never lost any zoas to it.

50/50 tank water and hydrogen peroxide (the regular 3%) for 4 minutes. They may not open until the next day.

 

[wunderlong88]

I would do my typical peroxide dip. I've seen it work wonders and I've never lost any zoas to it.

50/50 tank water and hydrogen peroxide (the regular 3%) for 4 minutes. They may not open until the next day.

I can do that for some but others I can't get the rock out.

 

[Mr. Mojo Rising]

I'm also leaning towards a pest of some kind.

Maybe you can list your livestock, including the inverts?

 

[wunderlong88]

I'm also leaning towards a pest of some kind.

Maybe you can list your livestock, including the inverts?

Ok. I did the peroxide dip yesterday morning. So far nothing has opened.

I have
Green Banded Goby
Purple Firefish Goby
Coral Beauty Angel
Starry Blenny
Diamond Goby
Dusky Wrasse
Maldives McCosker's Wrasse
Foxface Rabbitfish
2 Ocelleris Clowns
Melanarus Wrasse
Male blue star leopard wrasse
Longnose Butterfly Fish
Royal Gramma
Yellow Watchman Goby
Filefish
Majestic Angelfish
Tailspot Blenny
Mandarin Goby
Engineer Goby

I am home all of the time and never see any fish bothering these zoas. Not to mention I have a colony of zoas that seem to be unaffected by whatever is causing the issue.

Inverts:
various hermits
various snails
peppermint shrimp
serpent starfish
1 emerald crab (I think he is still in there)
1 pistol shrimp (not sure if he made it)
2 sea urchins (tuxedo, and another small one that camos himself)
asterina starfish (I have these but doesn't appear to be huge numbers) I know these might be the cause but I haven't found them on the zoas.

I can't think of anything else right now.

Thank you!

 

[subzero]

How long do you dip for?

 

[wunderlong88]

How long do you dip for?

4 minutes

 

[wunderlong88]

Fyi - I hadn't thought about this until today, but we have a 20 gal. in my son's room. The water circulates from our 180 to his tank and back (and through a 60 gal. refugium). He has zoas not open in his tank either. And all he has for fish are 2 cardinals, a lawnmower blenny and a watchman goby. He has a few crabs, snails and peppermint shrimp.

 

[wunderlong88]

Zoas are still closed. We dipped again in 50/50 peroxide/tank water a few days ago. Still no change.

 

[mcarroll]

I'm not saying to stop what you're doing, but IMO this just sounds like zoanthids being zoanthids.....they are temperamental...some of my least favorite corals as a result.

(If I want temperamental, I'll get fish!!!! )

It's very hard to inspect between polyps for pests....make sure you're as invasive as you need to be *at least once* to assure there's nothing hiding like a spider or little snail.